Does the Earth's magnetic field cause suicides?

Shumilov looked at activity in the Earth’s geomagnetic field from 1948 to 1997 and found that it grouped into three seasonal peaks every year&colon; one from March to May, another in July and the last in October.

Surprisingly, he also found that the geomagnetism peaks matched up with peaks in the number of suicides in the northern Russian city of Kirovsk over the same period.

Shumilov acknowledges that a correlation like this does not necessarily mean there is a causal link, but he points out that there have been several other studies suggesting a link between human health and geomagnetism.

Brain storms

Psychiatrists too have noticed a correlation between geomagnetic activity and suicide rates. A review of 13 years of South African data on suicides and magnetic storms in South African Psychiatry Review, vol. 6 p. 24) suggested a link.

Geomagnetic storms – periods of high geomagnetic activity caused by large solar flares – have also been linked to clinical depression.

What may be the cause of the link, if there is one, remains unknown. “The intriguing correlation between geomagnetism and suicide justifies more research into its mechanism,” says Rycroft.

Environmental cue?

“The most plausible explanation for the association between geomagnetic activity and depression and suicide is that geomagnetic storms can desynchronise circadian rhythms and melatonin production,” says Kelly Posner, a psychiatrist at Columbia University in the US.

The pineal gland, which regulates circadian rhythm and melatonin production, is sensitive to magnetic fields. “The circadian regulatory system depends upon repeated environmental cues to [synchronise] internal clocks,” says Posner. “Magnetic fields may be one of these environmental cues.”

There seems little doubt that the brain responds to electromagnetic fields – coils that generate electromagnetic fields can trigger muscular twitches when placed over a person’s skull.

However, Shumilov, who was presenting his data at the European Geoscience Union (EGU) annual meeting in Vienna, Austria, last week, does not believe geomagnetic activity influences everyone equally.

Suicide statistics

He also presented hospital data from 6000 pregnant women who had routine scans of their fetus’s heart rates between 1995 and 2003. In 15% of the fetuses, periods of disturbances in their heart rates coincided with periods of high geomagnetic activity.

The trouble with studying the causes of suicide is that it is a rare condition, says Klaus Ebmeier, a psychiatrist at the University of Oxford. “You are bound to get spurious effects. A study of the causes would have to enrol a country’s entire population.”

Cosmo Hallstrom, a member of the Royal College of Psychiatrists, agrees. “You have to be very careful with suicide statistics,” he says. “Countries report them differently. Catholic countries are very reluctant to diagnose suicide. Scandinavian countries consider it a social injustice not to.”

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